Aircraft Landing Gear Uplock Testing via Primary System Mediation
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Solution Overview
Problem
Current methods for testing alternate landing gear systems in aircraft are inefficient and may not promptly detect faults, requiring ground-based maintenance and potentially subjecting the gear to high loads and fatigue when extending under gravity.
Innovation Solution
The method involves the primary landing gear system holding the landing gear in place while the alternate system tests and moves the uplock from a locked to an unlocked configuration, allowing for faster identification of failures and reducing maintenance needs, and enabling testing without additional hardware, potentially during flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the alternate landing gear system is tested by releasing the uplock and extending the gear under gravity, then the functionality of the alternate system can be confirmed, but high loads and fatigue are imposed on the landing gear
Solution Approach 1:
The primary landing gear system acts as an intermediary to hold the landing gear in place during alternate system testing. Instead of allowing direct gravity-driven extension, the primary system's actuator controls the uplock movement, mediating the test process to prevent excessive loads while still enabling functionality verification of the alternate system.
2Reliability
If ground-based maintenance testing is performed on the alternate landing gear system, then faults can be detected, but turn-around time and maintenance complexity increase
Solution Approach 1:
The alternate landing gear system performs self-testing during normal flight operations without requiring external ground-based maintenance intervention. The system uses its own alternate actuator to move the uplock and verify functionality, enabling autonomous fault detection that eliminates dedicated maintenance testing time and reduces turn-around time.
3Ease of operation
If the uplock is moved during alternate system testing without holding the landing gear, then the test procedure is simpler, but the landing gear may drop under gravity causing high loads
Solution Approach 1:
The primary landing gear system serves as a controlling intermediary during the test procedure. Its actuator manages the uplock movement in a controlled manner, preventing uncontrolled gravity-driven drops while maintaining procedural simplicity. This mediation ensures both safety and ease of operation.
4Strength
If the primary landing gear system holds the landing gear in place during alternate system testing, then gravity-induced loads are reduced, but the primary system must remain operational during testing
Solution Approach 1:
The landing gear system is segmented into functionally independent primary and alternate systems. The primary system handles normal operations and can independently hold the gear in place, while the alternate system handles backup operations. This segmentation allows the primary system to serve as a stable platform for testing the alternate system without compromising overall system reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies maintenance, reduces turn-around times, and extends the life of the landing gear by minimizing loads and fatigue, while ensuring the alternate system's functionality is confirmed without the need for ground-based checks.
Implementation Method 1
the primary landing gear system holding the landing gear in place such that dropping of the landing gear under gravity is prevented
Implementation Method 2
the or each uplock is moved from a first configuration to a second configuration by the alternate landing gear system
Data Source
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AI summary
A method of extending a landing gear (201) of an aircraft (10) is disclosed. The aircraft (10) comprises an uplock (61) arranged to retain the landing gear (201) in a retracted position, a primary landing gear system (220) configured to retract and extend the landing gear (201), and an alternate landing gear system (230), independent from the primary landing gear system (220). The method comprises the primary landing gear system (220) holding the landing gear (201) in place while the uplock (61) is moved from a first configuration to a second configuration by the alternate landing gear system (230).